433 research outputs found
Forensic electrochemistry: the electroanalytical sensing of synthetic cathinone-derivatives and their accompanying adulterants in "legal high" products
The production and abuse of new psychoactive substances, known as âlegal highsâ which mimic traditional
drugs of abuse is becoming a global epidemic. Traditional analytical methodologies exist which can provide
confirmatory analysis but there is a requirement for an on-the-spot analytical screening tool that could be
used to determine whether a substance, or sample matrix contains such legal, or formally âlegal highsâ. In
this paper the electrochemical sensing of ( )-methcathinone and related compounds at a range of
commercially available electrode substrates is explored. We demonstrate for the first time that this class of
âlegal highsâ are electrochemically active providing a novel sensing protocol based upon their
electrochemical oxidation. Screen-printed graphite sensing platforms are favoured due to their proven
ability to be mass-produced providing large numbers of reliable and reproducible electrode sensing
platforms that preclude the requirement of surface pre-treatment such as mechanical polishing as is the
case in the use of solid/re-usable electrode substrates. Additionally they hold potential to be used on-site
potentially being the basis of an on-site legal high screening device. Consequently the electroanalytical
sensing of ( )-methcathinone (3a), ( )-40-methylmethcathinone [3b, 4-MMC, ( )-mephedrone] and
( )-40-methyl-N-ethylcathinone (3c, 4-MEC) is explored using screen-printed sensing platforms with the
effect of pH explored upon the analytical response with their analytical efficiency evaluated towards the
target legal highs. Interesting at pH values below 6 the voltammetric response quantitatively changes from
that of an electrochemically irreversible response to that of a quasi-reversible signature which can be used
analytically. It is demonstrated for the first time that the electroanalytical sensing of ( )-methcathinone (3a),
( )-mephedrone (3b) and 4-MEC (3c) are possible with accessible linear ranges found to correspond to
16â200 mg mL 1 for 3a (at pH 12) and 16â350 mg mL 1 for both 3b and 3c in pH 2, with limits of detection
(3s) found to correspond to 44.5, 39.8 and 84.2 mg mL 1 respectively. Additionally adulterants that are
commonly incorporated into cathinone legal highs are electrochemically explored at both pH 2 and 12
Regal electrochemistry: Sensing of the synthetic cathinone class of new psychoactive substances (NPSs)
© 2015 The Royal Society of Chemistry. In this paper the concept of 'Regal Electrochemistry' is expanded towards the electrochemical sensing of Novel Psychoactive Substances (NPSs) namely synthetic cathinone derivatives where British coinage is used as the electrochemical sensor. In this proof-of-concept approach, the electrochemical sensing of mephedrone (4-MMC) and 4âČ-methyl-N-ethylcathinone (4-MEC) is shown to be possible using a British 1 pence coin for the first time. This novel electrochemical protocol is validated towards the detection of cathinone derivatives in a seized street sample that has been independently analysed via high performance liquid chromatography demonstrating its potential use as a novel electrochemical sensor for NPSs
The Cost-Effectiveness of Reclassification Sampling for Prevalence Estimation
Typically, a two-phase (double) sampling strategy is employed when classifications are subject to error and there is a gold standard (perfect) classifier available. Two-phase sampling involves classifying the entire sample with an imperfect classifier, and a subset of the sample with the gold-standard.In this paper we consider an alternative strategy termed reclassification sampling, which involves classifying individuals using the imperfect classifier more than one time. Estimates of sensitivity, specificity and prevalence are provided for reclassification sampling, when either one or two binary classifications of each individual using the imperfect classifier are available. Robustness of estimates and design decisions to model assumptions are considered. Software is provided to compute estimates and provide advice on the optimal sampling strategy.Reclassification sampling is shown to be cost-effective (lower standard error of estimates for the same cost) for estimating prevalence as compared to two-phase sampling in many practical situations
Is health coaching effective in changing the health status and behaviour of prisoners?-a systematic review protocol
Abstract Background This is a protocol for a systematic review of the impact of health coaching on changing the health behaviour of offenders. Prisoners are more likely to suffer from health-related issues when compared to the general population. Health coaching has been shown to influence health outcomes of patients with chronic conditions. This review, therefore, aims to assess the effectiveness of health coaching interventions on the health of adolescent and adult offenders in custodial institutions. Methods We plan to conduct a systematic review of the current literature on health coaching interventions delivered in the prison setting. We will include randomised controlled trials and observational studies that compare health coaching to the usual care or other alternative interventions. The ideal interventions will be delivered either by health professionals or peer coaches, and the outcomes extracted in the data collection will be disease-specific, clientsâ life and self-management skills, behavioural and psychosocial outcomes. If appropriate, a meta-analysis of the data collected will be carried out on the last stage of the review. Discussion This systematic review will identify and gather evidence on the impact of health coaching interventions delivered in the prison setting and can function as a supporting material for health professionals, prison staff, the healthcare system, and public health departments when considering delivering health coaching. Systematic review registration PROSPERO CRD42016053237
Reassessment of the Lineage Fusion Hypothesis for the Origin of Double Membrane Bacteria
In 2009, James Lake introduced a new hypothesis in which reticulate phylogeny reconstruction is used to elucidate the origin of Gram-negative bacteria (Nature 460: 967â971). The presented data supported the Gram-negative bacteria originating from an ancient endosymbiosis between the Actinobacteria and Clostridia. His conclusion was based on a presence-absence analysis of protein families that divided all prokaryotes into five groups: Actinobacteria, Double Membrane bacteria (DM), Clostridia, Archaea and Bacilli. Of these five groups, the DM are by far the largest and most diverse group compared to the other groupings. While the fusion hypothesis for the origin of double membrane bacteria is enticing, we show that the signal supporting an ancient symbiosis is lost when the DM group is broken down into smaller subgroups. We conclude that the signal detected in James Lake's analysis in part results from a systematic artifact due to group size and diversity combined with low levels of horizontal gene transfer.Exobiology Program (U.S.) (Grant NNX08AQ10G)Assembling the Tree of Life (Program) (Grant DEB 0830024
Holographic Vitrification
We establish the existence of stable and metastable stationary black hole
bound states at finite temperature and chemical potentials in global and planar
four-dimensional asymptotically anti-de Sitter space. We determine a number of
features of their holographic duals and argue they represent structural
glasses. We map out their thermodynamic landscape in the probe approximation,
and show their relaxation dynamics exhibits logarithmic aging, with aging rates
determined by the distribution of barriers.Comment: 100 pages, 25 figure
Changes in grassland management and linear infrastructures associated to the decline of an endangered bird population
European grassland birds are experiencing major population declines, mainly due to changes in
farmland management. We analyzed the role of habitat availability, grazing management and
linear infrastructures (roads and power lines) in explaining spatial and temporal variation in the
population density of little bustards (Tetrax tetrax) in Portugal, during a decade in which the species
population size halved. We used data from 51 areas (totaling ca. 1,50,000 ha) that were sampled
in two different periods (2003â2006 and 2016). In 2003â2006, when the species occurred at high
densities, habitat availability was the only factor affecting spatial variation in bustard density. In the
2016 survey, variation in density was explained by habitat availability and livestock management,
with reduced bird numbers in areas with higher proportions of cattle. Population declines across the
study period were steeper in areas that initially held higher densities of bustards and in areas with a
higher proportion of cattle in the total stocking rate. Areas with higher densities of power lines also
registered greater density declines, probably due to avoidance behavior and to increased mortality.
Overall, our results show little bustards are currently lacking high quality grassland habitat, whose
persistence depends on extensive grazing regimes and low linear infrastructure densitiesinfo:eu-repo/semantics/publishedVersio
Simultaneous resection of colorectal cancer and synchronous liver metastases: what determines the risk of unfavorable outcomes? An international multicenter retrospective cohort study
BACKGROUND: The use of a simultaneous resection (SIMR) in patients with synchronous colorectal liver metastases (sCRLM) has increased over the past decades. However, it remains unclear when a SIMR is beneficial and when it should be avoided. The aim of this retrospective cohort study was therefore to compare the outcomes of a SIMR for sCRLM in different settings, and to assess which factors are independently associated with unfavorable outcomes. METHODS: To perform this retrospective cohort study, patients with sCRLM undergoing SIMR (2004-2019) were extracted from an international multicenter database, and their outcomes were compared after stratification according to the type of liver and colorectal resection performed. Factors associated with unfavorable outcomes were identified through multivariable logistic regression. RESULTS: Overall, 766 patients were included, encompassing colorectal resections combined with a major liver resection (n=122), minor liver resection in the anterolateral (n=407), or posterosuperior segments ('Technically major', n=237). Minor and technically major resections, compared to major resections, were more often combined with a rectal resection (29.2 and 36.7 vs. 20.5%, respectively, both P=0.003) and performed fully laparoscopic (22.9 and 23.2 vs. 6.6%, respectively, both P = 0.003). Major and technically major resections, compared to minor resections, were more often associated with intraoperative transfusions (42.9 and 38.8 vs. 20%, respectively, both P = 0.003) and unfavorable incidents (9.6 and 9.8 vs. 3.3%, respectively, both Pâ€0.063). Major resections were associated, compared to minor and technically major resections, with a higher overall morbidity rate (64.8 vs. 50.4 and 49.4%, respectively, both Pâ€0.024) and a longer length of stay (12 vs. 10 days, both Pâ€0.042). American Society of Anesthesiologists grades â„3 [adjusted odds ratio (aOR): 1.671, P=0.015] and undergoing a major liver resection (aOR: 1.788, P=0.047) were independently associated with an increased risk of severe morbidity, while undergoing a left-sided colectomy was associated with a decreased risk (aOR: 0.574, P=0.013). CONCLUSIONS: SIMR should primarily be reserved for sCRLM patients in whom a minor or technically major liver resection would suffice and those requiring a left-sided colectomy. These findings should be confirmed by randomized studies comparing SIMR with staged resections
Antibiotic Selection Pressure and Macrolide Resistance in Nasopharyngeal Streptococcus pneumoniae: A Cluster-Randomized Clinical Trial
Jeremy Keenan and colleagues report that during a cluster-randomized clinical trial in Ethiopia, nasopharyngeal pneumococcal resistance to macrolides was significantly higher in communities randomized to receive azithromycin compared with untreated control communities
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